effect of rotor speed and blade position in modified blade whitener on rice quality

the rotor of enegelberg whitener was equipped with a screw conveyor to reduce broken rice percentage. according to preliminary experiments this modification could reduce broken rice percentage about 2.5%. further experiment was performed to determine the effect of rotor speeds and blade positions on white rice quality. to do this, five rotor speeds, consisting 500, 600, 700, 800 and 900 r.p.m and three blade positions including, distance blade from entrance side of rotor was 7mm and from exit side was 9mm; distance blade from entrance side and exit side was 8mm equally; finally distance blade from entrance side of rotor was 9mm and from exit side was 7mm were examined using a experiment factorial randomized complete block design. the considered white rice quality measures were percentage of whole rice, broken rice, degree of milling and performance index. according to the result, rotor speed had significant effect on whole white rice and broken rice in level of 5%. blade position and the interaction of rotor speed and blade position had significant effect on degree of milling and performance index at level of 1% and 5% respectively. based on the results, the optimum operating conditions were 600 r.p.m and  distance blade from entrance side of rotor was 9mm and from exit side was 7mm. the rotor speed of 800r.p.m leads to same result.